1. Field of the Invention
The present invention relates to a work vehicle such as an agricultural tractor, more particularly to a work vehicle having a hood provided at a front portion of a vehicle body for covering an engine room.
2. Description of the Related Art
With some work vehicles such as tractors, a radiator is provided inside a hood and this hood includes a number of air vent holes in its right and left side faces and its front face, so that ambient air may be introduced from the right and left side faces and the front face toward the radiator. In the case of a conventional hood construction of this type, a vent hole area ratio (a ratio of vent forming area relative to a unit area of the total air vent hole forming portion) is fixedly set the same for each side face and the front face of the hood. That is, air vent holes of a same size are formed in the right and left side faces and the front face of the hood and also their disposing densities (the number of air vent holes per unit area) are fixedly the same (see e.g. Japanese Patent Application “Kokai” No. 2002-192961).
However, the radiator provided inside the hood is located close to the right and left side faces of the hood, but located far from the front face of the hood. Hence, there develops an air suction force difference between each side face and the front face of the hood, the air drawing force through the vent holes of the side face being greater than the air drawing force through the vent holes of the front face. This tends to result in clogging of the air vent holes of the side faces of the hood with various foreign objects such as grass, bugs, etc., As a result, there occurs shortage of cooling air to e.g. the engine inside the hood, which leads to such trouble as overheating of the engine, cooling problem of the air conditioner, etc.